This application claims the priority of patent application no. 101 29 165.5, filed in Germany on Jun. 11, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a locking system for an adjustable steering column having an adjusting device for adjusting the steering column in the vertical direction and having a locking device for the form-fitting locking of the steering column in the vertical direction, particularly for motor vehicles.
From European Patent Document EP 0 440 403 B1 (corresponds to U.S. Pat. No. 5,161,425) an adjustable steering column mechanism has become known, in which case, for adjusting a vertical position, a toothing is provided which is fixedly arranged on the vehicle body side and into which a tooth segment engages which is connected with the steering column. The tooth segment is prestressed by way of a swivellable eccentric.
U.S. Pat. No. 4,472,982 shows a swivelling device for a steering column. A console for the steering column is held swivellably about an axis fixedly arranged on the vehicle body. For fixing the adjusted position, a tooth segment extending radially with respect to the swivelling axis is provided on the vehicle-body-side receiving device. A counterpart connected with the console engages in this tooth segment.
From U.S. Pat. No. 4,541,298, it is known to provide toothed racks on a console for receiving a steering column. Gear wheels engage with the toothed racks; on the receiving device held on the vehicle body side, second toothed racks and respective corresponding gear wheels are situated. The pairs of gear wheels can be fixed with respect to one another by way of face-side toothings as soon as the gear wheels are braced with respect to one another by way of a tensioning axis.
German Patent Document DE 36 19 125 C1 (corresponds to U.S. Pat. No. 4,732,050) discloses an adjustable steering column of a motor vehicle, in the case of which pairs of tooth segments are arranged on both sides of the steering column. The pairs of tooth segments are perpendicularly arranged with respect to one another and can be fixed by means of a common tensioning device.
With respect to this state of the art, it is an object of the invention to provide a locking system for an adjustable steering column which is improved with respect to the required installation space.
According to the invention, this object is achieved by providing an adjustable steering column having a first adjusting device for adjusting the steering column in a vertical direction and a first locking device for form-fitting locking of the steering column in the vertical direction, wherein the first adjusting device comprises a vehicle-body-fixed swivel bearing for the steering column and a control arm which is swivellably held at a distance from the swivel bearing on the vehicle body, said control arm being disposed at the steering column in a sliding seat. According to certain preferred embodiments of the invention, it is suggested that the adjusting device includes a vehicle-body-fixed swivel bearing for the steering column and a control arm swivellably held at a distance thereto on the vehicle body. In this case, the control arm is disposed in a sliding seat on the steering column. As a result of this arrangement, the steering column according to the invention takes up very little space, because, depending on the arrangement of the sliding seat, the adjusting device does not project at all or projects only a little in its width beyond the steering column. As a result of the arrangement of the sliding seat below the steering column, installation space laterally to the steering column is required only for guiding the control arms past the steering column.
Advantageous further developments are described in the herein and in the claims.
It is suggested according to certain preferred embodiments of the invention to provide a console which accommodates the swivel bearing and the control arm. As a result of this measure, a steering column unit is formed which is closed in itself and which can be preassembled as a whole. Since all movable elements, that is, the swivel bearing and the control arm, are accommodated in the console, no additional adjustment will be required. This steering column unit, which is closed in itself, is also advantageous with respect to vibrations. The steering column unit need not be directly fastened to the vehicle body but can also be held on a cross member or on a bearing unit for the foot controls.
Furthermore, it is suggested according to certain preferred embodiments of the invention to construct the control arms as a box-type rocker device in order to increase the stiffness of the arrangement.
In addition, it is suggested according to certain preferred embodiments of the invention to cause the locking device to be applied to the sliding seat. As a result of this measure, the constructional expenditures as well as the required space are minimized. The sliding seat is as a rule arranged centrally on or under the steering column, so that a locking system which is effective here is arranged on or under the steering column but not laterally on the steering column. In addition, only a single locking system will be required.
It is suggested according to certain preferred embodiments of the invention to provide another adjusting device with an assigned locking device which are operative in the longitudinal direction of the steering column. In the case of this arrangement, a common operating device can advantageously be provided for both locking devices. Beyond the reduction of the constructional expenditures, this improves the operating reliability when adjusting the steering column because, as a result of the operation of the single operating device, the driver can completely unlock or lock the steering column.
In each case, the locking devices according to certain preferred embodiments of the invention comprises a corresponding pressure piece with a face-side toothing and a spring-loaded cone. The spring-loaded cone is guided parallel with respect to the tooth segment; the pressure piece is guided perpendicularly thereto. In the inoperative condition, the spring pushes the cone onto the pressure piece so that the face-side toothing of the pressure piece is pressed into the tooth segment. This locking device is locked in the inoperative condition and is unlocked by a displacement of the conical piece against the force of the spring. The use of a cone is advantageous because of the line contact between the cone and the pressure piece; however, in principle, other, particularly wedge-shaped elements can also be used instead of the cone. When, viewed in the direction of the force of gravity, the pressure piece is arranged below the tooth segment, a simplified unlocking of the locking device is achieved because the force of gravity will disengage the pressure piece when the cone is pushed back. The tooth segment can be worked directly into the component to be secured. For the adjustment in the longitudinal direction, the tooth segment can, for example, be worked as a toothing on the exterior side into a jacket tube, the jacket tube being longitudinally displaceably guided in the steering shield tube. The pressure piece is then guided in a slot which is arranged on the steering shield tube. Such an arrangement is known, for example, from German Patent Document DE 44 13 798 A1.
When the cones are arranged so that their tapered end is arranged in the driving direction, there is also the advantage that, in the event of a frontal collision, the locking devices are additionally loaded in the locking direction as a result of the occurring accelerations, so that the locking effect is intensified and a displacement of the steering column by an opening of the locking device can be reliability prevented.
In the case of the locking device operating in the vertical direction, the tooth segment can, for example, be connected by way of an arm with a movable part of the sliding seat according to certain preferred embodiments of the invention. The tooth segment is then preferably also guided on the steering shield tube, and a slot receiving the pressure segment is arranged in the area of this guidance on the steering shield tube. In the case of such an arrangement, it is particularly easily possible to advantageously arrange the two locking devices in a locally adjacent manner. Such an arrangement has the advantage that the common operation of the locking devices can be achieved at low constructional expenditures.
Finally, it is an advantage for the two locking devices to be constructed such that largely identical constructional elements can be used according to certain preferred embodiments of the invention. Thus, for example, the pressure pieces and the cones can be constructed as identical parts.
The two locking devices can be arranged in an aligned manner according to certain preferred embodiments of the invention. In this case, the machining expenditures will be reduced because the required bores can be produced in a single setting. The casting tool for the housing can also have a simpler design and slides of the casting tool can be combined.
The two locking devices may be arranged to be equally acting or oppositely acting according to certain preferred embodiments of the invention. In the case of an equally acting arrangement, the joint operating device should be provided at the end of the two locking devices situated behind one another. In the case of oppositely acting locking devices, the joint operating device should be arranged between the locking devices.
The two locking devices may be operated simultaneously or successively according to certain preferred embodiments of the invention. When they are operated simultaneously, an activating of the operating device will open both locking devices, and the steering column can be freely moved in the vertical and longitudinal direction. When the operation takes place successively, an intermediate position of the operating device may be provided, in which the steering column can be adjusted, for example, only in the vertical direction. Only when the operating device has reached its end position as a result of a second activating, will the steering column be freely movable in the vertical and longitudinal direction.
An electric geared motor or a manual operating device can be provided as an operating device for the two locking devices according to certain preferred embodiments of the invention. The manual operating device preferably comprises a handle which is rotatably disposed and, for generating a longitudinal movement, is held on a spiral-shaped ramp. A pull rod connected with the handle penetrates the spring-loaded cones and transmits the longitudinal movement of the handle to the cones.
The use of the adjustable steering column according to the invention is preferably provided for motor vehicles, but is not limited thereto.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.